Table 3.
Surgical factors
| Baseline characters | LHBL (n = 1208) | HHBL (n = 236) | p-value |
|---|---|---|---|
| Left/right knee (n, %) | 579 (47.9)/629 (52.1) | 135 (57.2)/101 (42.8) | 0.009a |
| ASA grade ≥ 3 (n, %) | 32 (2.6) | 3 (1.3) | 0.208b |
| Anaesthetic (n, %) | 0.324a | ||
| General | 552 (45.7) | 107 (45.3) | |
| Spinal | 15 (1.2) | 5 (2.1) | |
| Epidural | 79 (6.5) | 22 (9.3) | |
| Regional | 17 (1.4) | 5 (2.1) | |
| Combined | 545 (45.1) | 97 (41.1) | |
| CMTKA/RTKA (n, %) | 957 (79.2)/251 (20.1) | 220 (93.2)/16 (6.8) | < 0.001a |
| Tourniquet use (n, %) | 982 (81.3) | 190 (80.5) | 0.778a |
| Tourniquet time (min) | 54.0 (34.0, 71.8) | 55.0 (34.0, 75.8) | 0.207b |
| Prosthesis type(n, %) | 0.339a | ||
| CR | 26 (2.2) | 6 (2.5) | |
| PS | 1151 (95.3) | 220 (93.2) | |
| others | 31 (2.6) | 10 (4.2) | |
| Operation time (min) | 110.0 (95.0, 126.0) | 115.0 (100.0, 132.8) | 0.002b |
| IBL > 20% (n, %) | 163 (13.5) | 49 (20.8) | 0.004a |
| IBL (mL) | 367.6 (150.8, 613.8) | 403.8 (166.5, 716.2) | 0.206b |
| IBL/PBV (%) | 9.2 (3.7, 15.0) | 9.5 (4.2, 17.1) | 0.323b |
| Intraoperative transfusion (n, %) | 69 (5.7) | 18 (7.6) | 0.258a |
ASA American Society of Anesthesiologists classification, CMTKA conventional manual total knee arthroplasty, RTKA robotic-assisted total knee arthroplasty, CR cruciate-retaining prosthesis, PS posterior-stabilized prosthesis; others: including rotational knee system and prosthesis with stems; IBL Intraoperative blood loss, PBV patient’s blood volume
aPearson’s chi-square test
bMann–Whitney U-test